The thick, pungent left behind smells of a hot, sweaty, mungy ass sex session. Usually left behind in your room, dorm or car. A dead give away to the trained and experienced nostril like your mom's.
Although Carl told his mom he was doing homework with Cassie, the stanked up room was a dead giveaway that more than their lessons had been worked on.
Originally prison slang(as we know) for being stabbed by a crude improvised weapon. In area's like London(East london, North, West and South) It simply means stabbed-The word is used popularly by gangsters and delinquents.
Ill shank you bruv
Look yeah, duck out or ill shank you
You wanna get shanked?
Safe then ill shank you.